Shell Programming and Scripting

I have two files like this:
fileA.net

Code:

A
B
C

fileA.dat

Code:

1
2
3

and I want the output

output_expected

Code:

A 1
B 2
C 3

I know that the easier way is to do a paste fileA.net fileA.dat, but the problem is that I have 10,000 couple of files (fileB.net with fileB.dat; fileC.net with fileC.dat ....) and it is not feasible by hand.
So I tried to insert the next script into a loop for:

Code:

for a in *.net
do
  name=`echo $a |sed 's/.net/.dat`
  two=`cat $name`
  echo -e "$a"'\t'"two" > $a.output_observed
done

However, the output was
fileA.net.output_observed

Code:

A
B
C    1
2
3

Is it possible to apply the paste command for two variables? I tried this, but it was reported that the list is too long, or something like this. Somebody know a smart way to merge two columns of files with similar names in large scale, due to have 10,000 of files?

Best regards.

try this...

Code:

paste fileA fileB

Like this?

Code:

cd /wherever/files/are
find . -type f -name '*.net'|while IFS='/' read dummy a
do
 echo paste "$a" "${a/%net/dat}"
done > output

Remove the echo if this is working as expected.

Hi elixir_sinari,
thank you very much for your smart script. It is very useful and quick (each file has 1 millions of lines).

Best regards.